Improve conversion performance

[SethMMorton]

In addition to #57, #59, this PR optimizes performance across many aspects of fastnumbers. Some enhancements were algorithmic, some were utilizing more efficient libraries, and some were micro-optimizations and bithacks.

This PR also solves #28 by using a more robust string to double conversion function (the one mentioned in #57).

[codecov[bot]]

Codecov Report

Base: 91.64% // Head: 88.15% // Decreases project coverage by -3.50% :warning:

Coverage data is based on head (e8ef8c7) compared to base (c14959f). Patch coverage: 85.93% of modified lines in pull request are covered.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #60 +/- ## ========================================== - Coverage 91.64% 88.15% -3.50% ========================================== Files 5 6 +1 Lines 934 996 +62 ========================================== + Hits 856 878 +22 - Misses 78 118 +40 ``` | [Impacted Files](https://codecov.io/gh/SethMMorton/fastnumbers/pull/60?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Seth+Morton) | Coverage Δ | | |---|---|---| | [src/cpp/extractor.cpp](https://codecov.io/gh/SethMMorton/fastnumbers/pull/60?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Seth+Morton#diff-c3JjL2NwcC9leHRyYWN0b3IuY3Bw) | `89.74% <ø> (ø)` | | | [src/cpp/argparse.cpp](https://codecov.io/gh/SethMMorton/fastnumbers/pull/60?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Seth+Morton#diff-c3JjL2NwcC9hcmdwYXJzZS5jcHA=) | `71.24% <71.24%> (ø)` | | | [src/cpp/fastnumbers.cpp](https://codecov.io/gh/SethMMorton/fastnumbers/pull/60?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Seth+Morton#diff-c3JjL2NwcC9mYXN0bnVtYmVycy5jcHA=) | `84.88% <96.92%> (-0.12%)` | :arrow_down: | | [src/cpp/c\_str\_parsing.cpp](https://codecov.io/gh/SethMMorton/fastnumbers/pull/60?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Seth+Morton#diff-c3JjL2NwcC9jX3N0cl9wYXJzaW5nLmNwcA==) | `99.36% <100.00%> (-0.15%)` | :arrow_down: | | [src/cpp/parser.cpp](https://codecov.io/gh/SethMMorton/fastnumbers/pull/60?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Seth+Morton#diff-c3JjL2NwcC9wYXJzZXIuY3Bw) | `93.50% <100.00%> (+1.19%)` | :arrow_up: | Help us with your feedback. Take ten seconds to tell us [how you rate us](https://about.codecov.io/nps?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Seth+Morton). Have a feature suggestion? [Share it here.](https://app.codecov.io/gh/feedback/?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Seth+Morton)

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[SethMMorton]

Performance charts before-and-after for the drop-in-replacement functions. Granted, some of the poor "before" performance was bad decisions made in the C++ refactor and the current C implementation is slightly better, but for sure the "after" is much better than the current C implementation.

Python 3.7

Timing comparison of int functions

Before

Input type	builtin (ms)	fastnumbers (ms)
Small Int String	14.588 ± 0.366	11.751 ± 0.390
Int String	16.197 ± 2.065	16.573 ± 3.420
Large Int String	23.700 ± 1.429	28.062 ± 0.614
Int	9.575 ± 0.193	11.536 ± 3.479
Float	20.762 ± 2.199	24.159 ± 0.449

After

Input type	builtin (ms)	fastnumbers (ms)
Small Int String	14.186 ± 0.248	7.790 ± 0.138
Int String	15.145 ± 0.093	10.171 ± 0.949
Medium Int String	17.014 ± 0.271	10.367 ± 0.075
Large Int String	22.850 ± 0.070	21.071 ± 0.489
Int	9.258 ± 0.097	6.889 ± 0.079
Float	19.593 ± 0.538	20.350 ± 0.188

Timing comparison of float functions

Before

Input type	builtin (ms)	fastnumbers (ms)
Small Int String	12.193 ± 0.287	15.934 ± 2.573
Int String	12.841 ± 2.024	17.251 ± 4.057
Large Int String	38.674 ± 6.709	46.769 ± 2.007
Small Float String	14.901 ± 4.136	15.891 ± 1.810
Float String	31.982 ± 4.383	18.625 ± 1.801
Large Float String	55.922 ± 3.676	64.327 ± 3.662
Int	8.534 ± 0.885	11.937 ± 0.777
Float	7.511 ± 0.249	9.281 ± 1.310

After

Input type	builtin (ms)	fastnumbers (ms)
Small Int String	11.829 ± 0.092	9.585 ± 0.090
Int String	12.384 ± 0.560	9.919 ± 0.055
Medium Int String	13.359 ± 0.051	10.308 ± 0.167
Large Int String	35.909 ± 7.434	14.476 ± 0.049
Small Float String	12.384 ± 1.176	10.130 ± 0.288
Float String	29.721 ± 0.108	11.757 ± 1.495
Large Float String	52.927 ± 1.115	11.749 ± 0.270
Int	8.040 ± 0.050	8.839 ± 0.059
Float	7.213 ± 0.050	6.478 ± 0.057

Python 3.10

Timing comparison of int functions

Before

Input type	builtin (ms)	fastnumbers (ms)
Small Int String	9.833 ± 1.317	11.301 ± 0.952
Int String	10.943 ± 0.125	13.034 ± 0.129
Large Int String	17.007 ± 0.399	24.291 ± 0.805
Int	6.068 ± 0.049	10.130 ± 0.627
Float	15.456 ± 0.386	22.657 ± 0.311

After

Input type	builtin (ms)	fastnumbers (ms)
Small Int String	9.631 ± 0.476	7.466 ± 0.151
Int String	10.730 ± 0.715	9.469 ± 0.185
Medium Int String	11.573 ± 0.726	9.414 ± 0.098
Large Int String	16.108 ± 0.168	18.211 ± 0.764
Int	5.848 ± 0.814	6.317 ± 0.146
Float	15.029 ± 0.244	19.011 ± 0.175

Timing comparison of float functions

Before

Input type	builtin (ms)	fastnumbers (ms)
Small Int String	8.967 ± 0.509	14.056 ± 1.034
Int String	9.648 ± 0.184	14.064 ± 0.207
Large Int String	28.892 ± 1.026	40.313 ± 0.423
Small Float String	8.720 ± 0.081	13.713 ± 0.017
Float String	26.218 ± 0.220	15.497 ± 0.035
Large Float String	50.403 ± 0.354	61.001 ± 0.382
Int	4.739 ± 0.048	10.855 ± 0.017
Float	3.968 ± 0.051	8.958 ± 0.493

After

Input type	builtin (ms)	fastnumbers (ms)
Small Int String	8.512 ± 0.565	9.487 ± 0.746
Int String	9.216 ± 0.227	9.715 ± 0.150
Medium Int String	10.486 ± 0.162	10.028 ± 0.087
Large Int String	28.977 ± 1.327	14.435 ± 0.182
Small Float String	8.719 ± 0.304	9.946 ± 0.652
Float String	26.140 ± 0.447	11.401 ± 0.158
Large Float String	52.146 ± 1.277	12.464 ± 0.450
Int	4.869 ± 0.045	9.016 ± 0.121
Float	4.060 ± 0.064	6.736 ± 0.116